Circuit emulation service for carrying time division multiplexed scada traffic

A network node comprising:

• a serial interface for coupling to a serial link to communicate time division multiplexed (TDM) traffic;
• a packet interface for coupling to a packet switched network (PSN) to communicate packet traffic;
• a processor coupled to the serial and packet interfaces;
• a memory coupled to the processor;
• a program of computer readable instructions stored in the memory that when executed by the processor cause the network node to:
• determine if a TDM Supervisory Control and Data Acquisition (SCADA) message has been received over a serial link;
• if a TDM SCADA message has been received:
• encapsulate the TDM SCADA message in a circuit emulation service (CES) packet;
• if a TDM SCADA message has not been received:
• generate a filler frame;
• encapsulate the filler frame in a CES packet;
• set a serial number of the CES packet to null;
• and
• transmit the CES packet over the PSN.

A network node comprising:

• a serial link interface;
• a packet interface;
• and
• a circuit emulation service (CES) function adapted to be operable to encapsulate in a CES packet a TDM Supervisory Control and Data Acquisition (SCADA) message received over the serial link interface, to set a serial number of the packet to null, and to transmit the CES packet over the packet interface.